class Solution {
public:
    vector<vector<int>> generate(int numRows) {
        vector<vector<int>> vv;
        vv.resize(numRows);
        for(size_t i=0;i<vv.size();++i)
        {
            vv[i].resize(i+1,0);
            vv[i][0]=1;
            vv[i][i]=1;
        }
        for(size_t i=0;i<vv.size();++i)
        {
            for(size_t j=0;j<vv[i].size();++j)
            {
                if(vv[i][j]==0)
                    vv[i][j]=vv[i-1][j-1]+vv[i-1][j];
            }
        }
        return vv;
    }
};
